body{
    width: 100%;
    height: auto;
}
header{
    width: 100%;
    height: 4em;
}
section{
    position: relative;
    width: 100%;
    height: 40em;
}
.box{
    position: relative;
    top: 3em;
    width: 80%;
    height: 80%;
    margin: 0 auto;
    display: flex;
    flex-flow:row wrap;
    justify-content:start;
}
.box>div{
    width: 24.5%;
    height: 48%;
    margin: 0.2em;
}